In a lifting operation lasting just 20 minutes, Heerema Marine Contractors Nederland lifted the topsides off the former North Sea loading and storage buoy Brent Spar on the evening of 25 November as the first step in the conversion of the structure into a quay for Mekjarvik, near Stavanger.
The 1,600t topside, which is the control and accommodation superstructure visible above the water, was lifted at the Spar’s mooring at Vats in Norway using semi-submersible crane vessel the Thialf, one of the largest floating cranes in the world. A heavy-lift rigging frame was suspended from one of The Thialf’s twin cranes and attached to lifting points on the topsides. Removal of the topsides resulted in the base of the Spar, which weighs 12,900t, rising out of the water by about 7m. The lifted load was then carried 39km to shore for dismantling and scrapping at Vikaneset, north east of Stavanger.
Over the next four months, the remainder of the Spar is being gradually raised out of the water by another Heerema crane barge, the H851, working with the aid of lifting specialist PSC Heavy Lift. The huge hull is being cut into rings which will be cleaned and placed on the seabed at Mekjarvik, filled with ballast, and finished with a concrete surface to form the new quay. The quay is scheduled for completion by the end of the year.
The Spar recycling project is the result of an international engineering competition to find a viable and environmentally-sensitive way to decommission the Brent Spar by its owner Shell UK Exploration & Production, organised in the wake of an international outcry over its initial plans simply to dump the structure at sea.
